The Milton Work Point Count (A=4 - K=3 - Q=2 - J=1) has been around for about a century. Originally introduce by Milton Work for the games of Whist and Auction bridge he later also introduced it as the valuation method for balanced hands in contract bridge when this game became popular.
In due course the Milton Point Count was used by Charles Goren for the evaluation of all bridge hands by adding to it the concept of shortage points valuation.

This valuation system has been hugely successful for decades but, as bidding systems became more sophisticated and competition became evermore fiercer deficiencies have started to emerge, especially from the late 1980s onwards.

From my main stream (local club level) perspective four issues have arisen during the past 25 years or so :

1. The Shortage point valuation does not adequately reflect the strength of unbalanced hands.

2. Statistical analysis has revealed that on average 55% of hand combinations of 25 points are of sufficient strength to fulfill a Game contract.   In the fierce modern competition environment this has become acceptable.

3. Tens are not included in the traditional Milton Point Count. Statistical analysis has shown that they should.

4. Statistical analysis has also shown that Aces and Kings in balanced hands are substantially overvalued by the traditional Milton Point Count.

1. Shortage
The concept of The Losing Trick Count was originally published by Courtenay and Walsh in 1935 and later again by Harrison-Gray in 1961. But it was not until after Ron Klinger's publication of The Modern Losing Trick Count in 1987, that this (not so) "new" concept started to become adopted wide spread as a better method (than using shortage points) to assess hand shapes, especially shortages.

2. The 25 point Game contract
As a result of this finding the Standard (American) Bidding system has by many players been modified, featuring a 15-17 point 1NT opening (instead of 16-18), an indiscriminate 12 point minimum opening (in 1st or 2nd position, instead of 13) and a new suit response at the 2 level with 10+ points (rather than 11+).

3. Valuation of the 10s
Statistical analysis first published by Richard Cowan ("Applied Statistics", Journal of the Royal Statistical Society, 1987) and recently extended by David Jackson & Ron Klinger (Better Balanced Bidding - The Banzai Method, 2010) clearly show that 10s should be included in a proper hand valuation system. The latter authors recommend the Extended Milton Point Count :

4. Overvaluation of A and K in balanced hands
Statistical analyses (by the authors quoted under '3' above) clearly reveal that Aces and Kings in balanced hands are overvalued by 10% combined (resp. 6.7% + 3.3%) by the original Milton Point Count. Queens are about right and Jacks and 10s are undervalued by 10% combined.   Jackson and Klinger propose for Intermediate to Advanced players the new "Banzai Point Count" which accurately reflects the statistical findings :

The Jazclass - Bridge Course approach

The Jazclass Bridge Course now uses the Extended Milton Point Count approach throughout. This increases the total points in a pack from 40 to 42 High Card Points, and as a consequence statistically restores the minimum Game contract requirement from 25* back to 26 points. This has the following advantages :

1. It restores the Standard (American) Bidding System to its (approximate) original values.

2. It reflects the Hand value with greater accuracy than the original Milton Point Count system.

3. It reduces the overvaluation of Aces and Kings in balanced hands by a third : to 6.7%.

4. It incorporates the more aggressive Game contract approach of recent years.
           ²⁵/₄₀= 62.5% of total trick taking power (ttp)         ²⁶/₄₂= 61.9% of total ttp

Obviously the Banzai Point Count is superior to Extended Milton. However it will probably take years before this system is fully in mainstream use. For the time being Extended Milton appears therefore the better option, especially for Beginners and most Intermediate players.

However I recommend that Intermediate players have at least a working knowledge of the Banzai Point Count, so that in borderline decisions of balanced hands it can be used as an additional valuation check.
Generally it is also useful to be aware that balanced hands containing mainly Aces and Kings are overvalued in point counts and those including several Jacks and/or 10s are undervalued.

With hand Combinations containing at least one unbalanced hand it is best to use a combination of Extended Milton, The Losing Trick Count and Quick Tricks for your valuation assessment.

Note *
As there are four 10s in a pack any hand should on average include one 10. Many 25 point hand combination (as valued by the old system) will therefore on average include two 10s and as a consequence have 26 points when valued using the Extended Milton Point Count.
(It is tempting to speculate that the 45% of old 25 point hands which statistically don't make a Game contract are in most cases perhaps deficient in 10s.)